Known insulating panel systems are complex and expensive to manufacture. Examples of known systems include that of Nowack, U.S. Pat. No. 4,635,422, which describes a system including inner and outer skins having an interlocking labyrinth seal, a central member and a separate clip. The patent to Eschbach, U.S. Pat. No. 3,712,005 describes extrusions for partitions, walls and enclosures which have straight linear ends to the inner and outer skins. Brzezinski, U.S. Pat. No. 3,527,010, describes a building wall construction used with glazing.